Structural Studies of Some Compounds Containing C2 Fragments Attached to Various Metal‐Ligand End‐Groups

The preparation, characterisation and single-crystal XRD molecular structure determinations of four complexes containing –CC–MLn end-groups, namely Ru{C≡CFc′(I)}(dppe)Cp (1), the vinylidene [Os(=C=CH2)(PPh3)2Cp]PF6 (2), trans-Pt(C≡CC6H4-4-C≡CPh){C≡CC6H4-4-C2Ph[Co2(μ-dppm)(CO)4]}(PPh3)2 (3), and C6H4{μ3-C2[AuRu3(CO)9(PPh3)]}2-1,4 (4) are reported. In these compounds a range of –CC– environments is found, extending from the σ-bonded alkynyl group in 1 to examples where the C2 unit interacts with either a proton (in vinylidene 2), by bridging a dicobalt carbonyl moiety (in 3) or the AuRu3 cluster in 4. Changes in geometry are rationalised by considering the various bonding modes.